PubMed Health⌕ Search

Biomedical subjects

L Hart

Publications and source records attributed to L Hart.

At least 19 recordsLinked to original sources
PubMed1991

The influence on blood pressure during daily activities of a single session of aerobic exercise.

Previous research has examined the effectiveness of a single session of aerobic exercise in lowering blood pressure responsivity to the subsequent presentation of a nonexercise stressor in the laboratory. This case study was designed to explore the possibility that a single session of aerobic exercise might lower blood pressure for up to 4 hours postexercise as the subject engaged in his usual activities at home and at work. The subject was an untrained, unmedicated, borderline hypertensive who underwent ambulatory blood pressure monitoring as he maintained a normal schedule of activities over a 5-day period. On 2 of the 5 days, the subject exercised at 8:30 AM for 30 minutes at 70% VO2max. Blood pressure readings on days when the subject read for 30 minutes were compared with readings on days when he exercised. He showed an average reduction in systolic blood pressure of 26.4 mm Hg at 2 hours after exercise, 24.2 mm Hg at 4 hours afterward, and 12.2 mm Hg at 9 hours after the exercise. Changes in diastolic blood pressure and heart rate were smaller and less consistent. The authors concluded that the modifying influence of a single session of aerobic exercise on blood pressure responsivity to subsequent laboratory-based stressors may also extend to the natural environment. The discussion addresses theoretical, methodological, and clinical considerations in the use of aerobic exercise to modify excessive blood pressure reactivity.

Adult↗
PubMed1991

Individual differences in children's response to pain: role of temperament and parental characteristics.

Sixty-five families were enlisted in a study exploring factors associated with distress behavior in 5-year-old children receiving diphtheria-tetanus-pertussis immunizations. At a home visit 1 month before the immunization, the following measures were obtained: (1) the Behavioral Style Questionnaire, a measure of temperament: (2) parental self-reports of medically related attributes (eg. "good patient"); (3) parental attitudes toward pain in children and responsiveness to their child's pain; and (4) parental prediction of distress at upcoming immunization. The child's distress behavior during the immunization was evaluated using a modification of the Procedure Rating Scale-Revised and, after the procedure, the child's assessment of his or her pain was elicited using the Oucher. Children's mean Procedure Rating Scale-Revised score was 2.57 of a possible 11. Thirty-one (48%) had low (less than or equal to 1) and 7 (11%) had high distress scores (greater than or equal to 2 SD above the mean). Factors positively correlated with distressed behavior included more "difficult child" cluster characteristics, the individual temperamental dimension of adaptability, but few parental attitudes and attributes. Parent's predictions of distress were the strongest correlates. These findings document the variation that children demonstrate in response to pain and offer some insight into associated innate and environmental factors. These results imply that treatment strategies derived from parental knowledge and tailored to individual characteristics of the child may be most effective in alleviating pain-related distress in medical settings.

Attitude↗
PubMed1990

The Duke AFM Program. Intensive induction chemotherapy for metastatic breast cancer.

Forty-five patients have completed treatment with AFM, an intensive induction chemotherapy regimen composed of Adriamycin (doxorubicin, Adria Laboratories, Columbus, Ohio), 5-fluorouracil, and methotrexate with folinic acid rescue. This regimen was designed to produce rapid and extensive tumor shrinkage prior to high-dose alkylating agent chemotherapy with autologous marrow support. The overall response rate was 91%, and 38% of patients achieved complete clinical responses after a mean of 70 days on treatment. Hematologic and mucosal toxicity were extensive, but no toxic deaths were noted. AFM is a potent remission induction regimen for metastatic breast cancer, but its considerable toxicity suggests caution in its use for routine breast cancer treatment.

Adult↗
PubMed1990

Detection of human immunodeficiency virus in infected CEM cells using fluorescent DNA probes and a laser-based computerized image cytofluorometry system.

Quantitative nonradioactive methods to measure the human immunodeficiency virus (HIV) in individually infected cells are needed for the direct assessment of HIV infection, for the evaluation of antiviral chemotherapy and for testing the efficacy of vaccines. As a first step in accomplishing this goal, we built an argon ion laser-based computerized image cytofluorometry (ALCIC) system and determined this instrument's ability to quantitatively measure HIV nucleotides in infected lymphocytes. ALCIC consisted of a 43-mW argon ion laser connected to a Zeiss Universal microscope via a fiberoptic cable, a charged coupled-device video camera, a video frame grabber and array processor and a Micro Vax II computer using computer programs written in FORTRAN. HIV RNA and DNA were detected in infected CEM lymphocytes in culture by in situ hybridization using acetylaminofluorene (AAF)-labeled HIV-DNA probes, a rabbit anti-AAF antibody and a fluorescein-labeled goat anti-rabbit antibody. ALCIC measurements showed that 61% of the CEM cells were infected and that quantitative differences were distinguishable within this group. The levels of fluorescein isothiocyanate (FITC) fluorescence were sixfold or more greater than that observed with the same system using a 100-W mercury lamp for illumination; the improved intensity of the laser-based system is due to greater excitation intensity of the laser and the matching of the excitation spectrum to the peak wavelength of FITC. ALCIC has potential clinical value for determining the effect of antiviral agents on HIV infection and for assessing the susceptibility of different cell types to infection.

DNA Probes↗
PubMed1989

Maximal aerobic exercise following prolonged sleep deprivation.

The effect of 60 h without sleep upon maximal oxygen intake was examined in 12 young women, using a cycle ergometer protocol. The arousal of the subjects was maintained by requiring the performance of a sequence of cognitive tasks throughout the experimental period. Well-defined oxygen intake plateaus were obtained both before and after sleep deprivation, and no change of maximal oxygen intake was observed immediately following sleep deprivation. The endurance time for exhausting exercise also remained unchanged, as did such markers of aerobic performance as peak exercise ventilation, peak heart rate, peak respiratory gas exchange ratio, and peak blood lactate. However, as in an earlier study of sleep deprivation with male subjects (in which a decrease of treadmill maximal oxygen intake was observed), the formula of Dill and Costill (4) indicated the development of a substantial (11.6%) increase of estimated plasma volume percentage with corresponding decreases in hematocrit and red cell count. Possible factors sustaining maximal oxygen intake under the conditions of the present experiment include (1) maintained arousal of the subjects with no decrease in peak exercise ventilation or the related respiratory work and (2) use of a cycle ergometer rather than a treadmill test with possible concurrent differences in the impact of hematocrit levels and plasma volume expansion upon peak cardiac output and thus oxygen delivery to the working muscles.

Adult↗
PubMed1989

The visual evoked potentials to the light emitting diode compared to the flash and pattern reversal stimulus.

Light-emitting diode (LED), flash (FL) and pattern reversal (PR) stimuli were used to elicit visual evoked potentials (VEPs) in 16 normal subjects (32 eyes) and 39 patients (78 eyes) with signs of visual system abnormality. Latencies and amplitudes (plus standard deviations) of 5 components of each response, correlation coefficients of the normal and abnormal responses and false negatives and positives are presented for the 3 kinds of stimuli. The data show that responses to LED stimuli are very similar to those of FL stimuli and should be useful in the operating room to monitor the visual pathways, if various endogenous factors known to affect late responses can be stabilized.

Adolescent↗
PubMed1985

Radiosensitivity of peripheral blood lymphocytes in autoimmune disease.

The proliferation of peripheral blood lymphocytes, cultured with Con A, can be inhibited by ionizing radiation. Lymphocytes from patients with conditions associated with autoimmunity, such as rheumatoid arthritis, systemic lupus erythematosus and polymyositis, are more radiosensitive than those from healthy volunteers or patients with conditions not associated with autoimmunity. The nuclear material isolated from the lymphocytes of patients with autoimmune diseases is, on average, lighter in density than the nuclear material from most healthy controls. This difference in density is not related to increased sensitivity to ionizing radiation but the degree of post-irradiation change in density (lightening) is proportional to the initial density, i.e. more dense nuclear material always shows a greater upward shift after radiation. The recovery of preirradiation density of nuclear material, 1 h after radiation exposure, taken as an indication of DNA repair, correlates with the radiosensitivity of lymphocyte proliferation (Con A response); failure to return to pre-irradiation density being associated with increased sensitivity of proliferative response. These results require extension but, taken with previously reported studies of the effects of DNA methylating agents, support the idea that DNA damage and its defective repair could be important in the aetio-pathogenesis of autoimmune disease.

Adult↗
PubMed1984

Interpretation of Doppler segmental pressures in peripheral vascular occlusive disease.

Measurement of Doppler segmental arterial pressures in the lower extremity using narrow pneumatic cuffs has become a standard noninvasive diagnostic technique. Correlation between arteriographic and noninvasive studies was available for 345 aortoiliac segments and 326 femoropopliteal segments. If stenoses of 50% or greater and occlusions were considered hemodynamically significant, the sensitivity to aortoiliac disease was 97%, but only 67% to femoropopliteal disease. The specificity for hemodynamically insignificant disease was 50% and 68%, respectively. Accuracy was influenced by the presence of associated aortoiliac or femoropopliteal disease. The sensitivity to hemodynamically significant femoropopliteal disease was 55% if there was associated aortoiliac disease, and 89% in its absence. In the presence of significant femoropopliteal disease, specificity for the absence of aortoiliac disease decreased from 70% to 41%.

Angiography↗
PubMed1984

Controlled trial of clinical utility of serum salicylate monitoring in rheumatoid arthritis.

A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used.

Arthritis, Rheumatoid↗
PubMed1983

Impedance plethysmography. Noninvasive diagnosis of deep venous thrombosis and arterial insufficiency.

The versatility of impedance plethysmography (IPG) in the diagnosis of arterial and venous disease was evaluated in the clinical setting. Eighty-eight consecutive patients suspected of acute or chronic deep venous thrombosis (DVT) and undergoing ascending venography were evaluated using IPG. Venous capacitance (VC) and venous outflow (VO) were expressed as a per cent impedance change (% delta I). The evaluation was considered as abnormal if the VC was less than 1.85% delta I and the VO less than 0.95% delta I. The overall accuracy was 90 per cent with a sensitivity of 92 per cent and specifity of 93 per cent. Arterial blood flow (ABF) was measured in normal volunteers (20 limbs) and patients with intermittent claudication (20 limbs) and rest pain (16 limbs). Resting ABF (cc/100 ml/min) did not differ (P greater than 0.05) in the normal volunteer (4.3 +/- 0.4) and patients with intermittent claudication (4.6 +/- 0.5), but both were significantly greater (P less than 0.05) than ABF in patients with rest pain (3.2 +/- 0.2). Peak ABF during reactive hyperemia (RH) was significantly greater (P less than 0.001) in normal volunteers (24.8 +/- 1.6) than in claudicators (10.5 +/- 1.3), and both flows were significantly greater (P less than 0.0001) than the peak ABF in patients with rest pain (5.3 +/- 0.5). IPG may be used in the assessment of arterial and venous disease. It provides a sensitive test with which to screen patients with suspected DVT. In addition, it is a valuable adjunct in differentiating normal limbs from those with intermittent claudication and/or rest pain.

Arterial Occlusive Diseases↗
PubMed1979

Relationship of sociodemographic and drinking variables to differentiated subgroups of alcoholics.

The results suggest that the sociodemographic variables of age, living arrangements, number of dependents, the drinking variable, and the client's perception of the type of drinker he is are the most strongly related to the derived typology. The exact relationship of these variables, as well as the variables that were moderately related to the typology, is not apparent. There is a pattern, however, that appears to run through the categories of the classification. The evidence suggests that for alcoholics to be in their prime earning years, living with their spouses, perceiving themselves as alcoholic, possessing marketable skills, and a recent history of abstinence seems to increase the likelihood of psychological need satisfaction. The antithesis--to be alcoholic, less than 30 or older than 50 years old, living by oneself or with parents, perceiving oneself as a social or problem drinker, and possessing a recent history of drinking--seems to decrease the likelihood of psychological need satisfaction. There seems to be a relationship between drinking behavior and psychological need satisfaction. As a group, the members of Clusters Two, Three, and Four are unable to abstain for longer than a week; Clusters Two and Three both possess physiological problems of adjustment. The members of Clusters One and Five tend to be able to abstain for longer periods. Cluster One is devoid of physiological difficulties, whereas Five has borderline problems. The physiological subscale of the Human Service Scale assesses the absence of symptoms associated with poor health (Realges & Butler, 1976). It appears that aberrant drinking does not necessarily result in self-perceived physiological-health complaints. These results are at variance with the belief that ethanol ingestion by an alcoholic and the resulting pathological complications are the predominant difficulties encountered by these persons. Thus it seems to us that a distraught life situation (that is, the lack of social and demographic assets--marriage, education, and so on) contributes to self-perceived severity of psychological need deprivation and not solely aberrant drinking. Therefore, in terms of recovery from alcoholism, these results argue against a unidimensional approach toward the treatment of alcoholism; that is, an approach that focuses solely on the drinking as "the" problem. A more strategic approach would include a thorough medical, psychiatric, psychological, social and vocational evaluation of the alcoholic's life situation, which in turn would permit mobilizing the efforts of a multidisciplinary team whose goal would be to maximize the resources and enhance the life situation of the alcoholic. It is hoped that the results of this study serve to increase our understanding of those factors that influence aberrant drinking.

Adult↗
PubMed1979

A canonical correlation analysis of the Alcohol-Use Inventory and the Human Service Scale.

The responses of 312 persons with alcoholism to the Alcohol-Use Inventory and Human Service Scale were subjected to canonical correlation analysis. Results indicate that the relationship between alcohol-use constructs and psychological need satisfaction can be explained by two axes: a personal security--social dimension and a personal stress--environmental dimension. Microanalysis of the variates indicated that emotional need satisfaction was differentially influenced by social and physiological variables.

Adolescent↗
PubMed1977

Medicine at McMaster; an innovative programme for undergraduates.

An innovative programme in undergraduate medical education, developed at the McMaster Medical School in Hamilton, Canada, is described. A number of features distinguish the McMaster approach from the more traditional system. Among these is a firm commitment to well-defined goals which stress the need for comprehensive patient care and an awareness of changing patterns of health delivery. Emphasis is placed on the student as the focal point in the educational process and a flexible curriculum provides the medium through which all facets of this novel system can best find expression.

Curriculum↗